DESCRIPTION : Mentoring and Training Activities The proposed CDA-2 is designed to promote Dr. Hall's transition to an independent Rehabilitation Research career under the mentorship of leading researchers in the areas of physical function, PTSD, and chronic disease management. The training plan for this CDA-2 includes a mix of didactic and experiential learning activities. The primary objectives of this training plan include: develop competency in cognitive- behavioral approaches to reducing PTSD symptoms; develop hands-on experience and utilize innovative mobile health technologies; develop expertise in physical activity interventions for Veterans with PTSD and the development of comparative effectiveness clinical trials; and continued professional development in the areas of manuscript preparation, grant proposals, and the responsible conduct of research. There is substantial evidence that physical inactivity contributes to poorer physical health outcomes in older adults. There is a paucity of work examining physical activity in Veterans with PTSD. Consequently, the efficacy of exercise as a beneficial adjunctive therapy in the treatment for PTSD symptoms and related health sequelae has not been established. Methods: Eighty Veterans 60 years and older with PTSD will be recruited from the Durham VAMC PTSD clinic to participate in a 12-week physical activity program consisting of aerobic and strength-training activities. Participants will be randomized to an intervention arm or usual care. Outcomes: Changes in physical function, PTSD symptom severity, and aerobic endurance will be assessed between the two study arms. Secondary outcomes include compliance with the intervention, pain, sleep, and psychological well-being. Summary: This pilot trial will extend our understanding of the physical and psychological benefits of physical activity in Veterans with PTSD. The results from this study will be used to be used to develop a larger, randomized controlled exercise trial for Veterans with PTSD. Once new, effective exercise therapies for Veterans with PTSD are established, we can augment traditional PTSD therapy with exercise therapy to promote the prevention and treatment of chronic diseases common in this vulnerable population.